While the multi-brand strategy didn't work for Yahoo, Yahoo had many other integration/prioritization problems.
The fact that YouTube had a different, more-market-appropriate name than 'Google Video' was important for its identity and success. (Or is Google going to rename YouTube to "Google+ Video", now?)
'Blogger' is a uniquely-interesting brand for them to throw away. If launched today, the word would almost be too generic for trademark protection. But its history practically grandfathers it in: its popularity was part of the mechanism by which 'blog' became a generic term.
'Google Blogs'? Blah.